Define diffusion
The net movement of particles from an area of high concentration to an area of low concentration
Three factors that affect the rate of diffusion
Concentration gradient, temperature, surface area
What is a high concentration
A large number of particles per unit volume
What is a low concentration
A small number of particles per unit volume
What does it mean to move down the concentration gradient
Move from a high concentration to a low concentration
What is an example of diffusion in plants
Oxygen diffusing into the blood from the alveoli
What is an example of diffusion in plants
Carbon dioxide diffusing into the leaf from the air
Define osmosis
The net movement of water particles from a dilute to concentrated through a partially permeable membrane
What is a partially permeable membrane
A barrier that allows some substances to pass through whilst blocking others
Describe the concentration of water particles in a dilute solution
High
Concentration of water particles in a concentrated solution
Low
What happens when an animal cell is placed in a concentrated solution
Will swell and burst
What happens when an animal cell is placed in a concentrated solution
Shrivel
Why must a plant tissue be dried before placed on a scale
To remove excess water
Why is percentage change in mass used
To allow plant tissues do different sizes to be compared
What will happen to the mass of a cell if water moves into it
Increase
What will happen to the mass of a cell if water moves into it by osmosis
Decrease
Define active transport
Movement of substances against the concentration gradient requiring energy from respiration
What does active transport require
Energy from respiration
How do particles move in active transport
From high to low conc
What does it mean to move against the conc gradient
Move from a low conc to a high conc
